A reference set of health utilities for long-term survivors of prostate cancer: population-based data from Ontario, Canada

Evaluating the correlations of cost and utility parameters from summary statistics for probabilistic analysis in economic evaluations

OBJECTIVES

The correlations between economic modeling input parameters directly impact the variance and may impact the expected values of model outputs. However, correlation coefficients are not often reported in the literature. We aim to understand the correlations between model inputs for probabilistic analysis from summary statistics.

METHODS

We provide proof that for correlated random variables X and Y (e.g. inpatient visits and outpatient visits), the Pearson correlation coefficients of sample means and samples are equal to each other (c o r r X , Y = c o r r X - , Y - ). Therefore, when studies report summary statistics of correlated parameters, we can quantify the correlation coefficient between parameters.

RESULTS

We use examples to illustrate how to estimate the correlation coefficient between the incidence rates of non-severe and severe hypoglycemia events, and the common coefficient of five cost components for patients with diabetic foot ulcers. We further introduce three types of correlations for utilities and provide two examples to estimate the correlations for utilities based on published data. We also evaluate how correlations between cost parameters and utility parameters impact the cost-effectiveness results using a Markov model for major depression.

CONCLUSION

Incorporation of the correlations can improve the precision of cost-effectiveness results and increase confidence in evidence-based decision-making. Further empirical evidence is warranted.

Quality of life in home-dwelling cancer patients aged 80 years and older: a systematic review

OBJECTIVE

Quality of Life (QoL) in elderly cancer patients is a topic that has been little explored. This systematic review aims to identify, assess, and report the literature on QoL in home-dwelling cancer patients aged 80 years and older and what QoL instruments have been used.

METHODS

We systematically searched the databases of Medline, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), PsykINFO, Scopus, Epistemonikos and Cinahl to identify studies of any design measuring QoL among home-dwelling cancer patients aged 80 years and older. We screened the titles and abstracts according to a predefined set of inclusion criteria. Data were systematically extracted into a predesigned data charting form, and descriptively analyzed. The included studies were assessed according to the Critical Appraisal Skills Programme (CASP) checklists, and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement (PRISMA) checklist was used to ensure rigor in conducting our investigations and reporting our findings. This systematic review was registered in PROSPERO (CRD42021240170).

RESULTS

We included three studies that specifically analyze QoL outcomes in the subgroup of home-dwelling cancer patients aged 80 years and older, with a total of 833 participants having various cancer diagnoses. 193 of the participants included in these three studies were aged 80 years or more. Different generic and cancer-specific QoL instruments as well as different aims and outcomes were studied. All three studies used a diagnosis-specific instrument, but none of them used an age-specific instrument. Despite heterogeneity in cancer diagnoses, instruments used, and outcomes studied, QoL in home-dwelling cancer patients aged over 80 years old seems to be correlated with age, physical function, comorbidity, living alone, needing at-home care services, being in a poor financial situation and having a small social network.

CONCLUSION

Our systematic review revealed only three studies exploring QoL and its determinants in the specific subgroup of home-dwelling cancer patients aged 80 years and over. A gap in the knowledge base has been identified. Future studies of this increasingly important and challenging patient group must be emphasized. Subgroup analyses by age must be performed, and valid age and diagnosis specific QoL instruments must be used to generate evidence in this segment of the population.

Cost-effectiveness analysis of primary treatments for localised prostate cancer: A population-based Markov analysis using real-world evidence

OBJECTIVE

We evaluate cost-effectiveness of primary treatments for localised prostate cancer by uniquely combining prospectively collected real-world outcomes and costs from UCSF Cancer of Prostate Strategic Urologic Research Endeavor (CaPSURE™).

METHODS

Markov models assessed cost-effectiveness of radical prostatectomy (RP), brachytherapy, electron beam radiation therapy (EBRT) and brachytherapy with EBRT by risk from US payers perspective over 8 years. Treatment costs included office visits, hospitalisation, procedures, medication and long-term care. Patients' surveyed HRQoL were mapped into utilities. Incremental cost-effectiveness ratios (ICERs) used cost per quality-adjusted life years (QALYs) and willingness-to-pay of $150,000/QALY.

RESULTS

Cost-effectiveness analysis (CEA) showed for low-risk prostate cancer, EBRT dominated the lowest cost brachytherapy, but RPns and brachytherapy plus EBRT were cost-effective compared to brachytherapy with ICERs of $18,926 and $41,662 per QALY. In medium-risk patients, RP, EBRT and brachytherapy plus EBRT all were cost-effective compared with brachytherapy, with ICERs of $30,604, $22,588 and $21,627/QALY. In high-risk, brachytherapy dominated all treatments. Procedure cost and utility are driving ICER, but probabilistic sensitivity analysis showed the model was robust across variables.

CONCLUSION

This first CEA combining prospective real-world evidence for HRQOL outcomes with costs shows cost-effectiveness of treatments vary by risk groups, providing new evidence for treatment decisions.

Cost-utility analysis of apixaban compared with usual care for primary thromboprophylaxis in ambulatory patients with cancer

Background:

Apixaban (2.5 mg) taken twice daily has been shown to substantially reduce the risk of venous thromboembolism (VTE) compared with placebo for the primary thromboprophylaxis of ambulatory patients with cancer who are starting chemotherapy and are at intermediate-to-high risk of VTE. We aimed to compare the health system costs and health benefits associated with primary thromboprophylaxis using apixaban with those associated with the current standard of care (where no primary thromboprophylaxis is given), from the perspective of Canada’s publicly funded health care system in this subpopulation of patients with cancer over a lifetime horizon.

Methods:

We performed a cost–utility analysis to estimate the incremental cost per quality-adjusted life-year (QALY) gained with primary thromboprophylaxis using apixaban. We obtained baseline event rates and the efficacy of apixaban from the Apixaban for the Prevention of Venous Thromboembolism in High-Risk Ambulatory Cancer Patients (AVERT) trial on apixaban prophylaxis. We estimated relative risk for bleeding, risk of complications associated with VTE treatment, mortality rates, costs and utilities from other published sources.

Results:

Over a lifetime horizon, apixaban resulted in lower costs to the health system (Can$7902.98 v. Can$14 875.82) and an improvement in QALYs (9.089 v. 9.006). The key driver of cost–effectiveness results was the relative risk of VTE as a result of apixaban. Results from the probabilistic analysis showed that at a willingness to pay of Can$50 000 per QALY, the strategy with the highest probability of being most cost-effective was apixaban, with a probability of 99.87%.

Interpretation:

We found that apixaban is a cost-saving option for the primary thromboprophylaxis of ambulatory patients with cancer who are starting chemotherapy and are at intermediate-to-high risk of VTE.

Elicitation of Health Utilities in Oncology in the Kingdom of Saudi Arabia

PURPOSE

Health utilities (HUs) are quantitative measures of quality of life that are used to derive outcomes such as quality-adjusted life years in cost-effectiveness analyses. In the Kingdom of Saudi Arabia, there are no HUs for cancer. This study aimed to generate HU estimates for various health states associated with cancer in the Kingdom of Saudi Arabia.

METHODS

Adult citizens of the Kingdom of Saudi Arabia, patients with cancer, and patients without cancer were recruited to participate in an online version of the Time Trade-Off (TTO) survey, a direct method that asks participants to indicate the amount of time they are willing to trade off in return for full health. The time horizon was 10 years. Patients were surveyed on their own health state; patients without cancer were presented with a scenario describing stage III colon cancer and were asked to act as proxies.

RESULTS

Mean HU score was 0.398 (n = 398), 0.315 for patients with cancer (n = 199), and 0.482 for patients without cancer (n = 199). Among patients, the largest subgroup with colorectal cancer (n = 105), had a mean HU of 0.296; the subgroup with the lowest mean HU was patients with hepatocellular cancer (n = 3; 0.047), and the subgroup with the highest mean HU was patients with cholangiocarcinoma (n = 5; 0.508). Overall, the initial stage I subgroup (n = 7) had a mean HU of 0.456; initial stage II (n = 25), 0.240; stage II (n = 67), 0.319; and initial stage IV (n = 77), 0.320.

CONCLUSION

To our knowledge, this is the first study of this size to elicit HU scores for cancer in the Kingdom of Saudi Arabia. Patients may have had clinically worse disease than the patients in the scenario that was presented to patients without cancer. Further analyses are warranted for specific types of cancer. These HUs can in turn be applied in cost-utility analyses.

Economic evaluation of robot-assisted radical prostatectomy compared to open radical prostatectomy for prostate cancer treatment in Ontario, Canada

INTRODUCTION

Recent health technology assessments (HTAs) of robot-assisted radical prostatectomy (RARP) in Ontario and Alberta, Canada, resulted in opposite recommendations, calling into question whether benefits of RARP offset the upfront investment. Therefore, the study objectives were to conduct a cost-utility analysis from a Canadian public payer perspective to determine the cost-effectiveness of RARP.

METHODS

Using a 10-year time horizon, a five-state Markov model was developed to compare RARP to open radical prostatectomy (ORP). Clinical parameters were derived from Canadian observational studies and a recently published systematic review. Costs, resource utilization, and utility values from recent Canadian sources were used to populate the model. Results were presented in terms of increment costs per quality-adjusted life years (QALYs) gained. A probabilistic analysis was conducted, and uncertainty was represented using cost-effectiveness acceptability curves (CEACs). One-way sensitivity analyses were also conducted. Future costs and QALYs were discounted at 1.5%.

RESULTS

Total cost of RARP and ORP were $47 033 and $45 332, respectively. Total estimated QALYs were 7.2047 and 7.1385 for RARP and ORP, respectively. The estimated incremental cost-utility ratio (ICUR) was $25 704 in the base-case analysis. At a willingness-to-pay threshold of $50 000 and $100 000 per QALY gained, the probability of RARP being cost-effective was 0.65 and 0.85, respectively. The model was most sensitive to the time horizon.

CONCLUSIONS

The results of this analysis suggest that RARP is likely to be cost-effective in this Canadian patient population. The results are consistent with Alberta's HTA recommendation and other economic evaluations, but challenges Ontario's reimbursement decision.

A Systematic Review and Meta-Analysis of Prostate Cancer Utility Values of Patients and Partners Between 2007 and 2016

Background. There is widespread agreement that both the length and quality of life matter when assessing new technologies and/or models of care in the treatment for cancer patients. Quality of life for partners/carers also matters, particularly for prostate cancer. Purpose. This systematic review aims to provide up-to-date utility values along the prostate cancer care continuum (i.e., from prescreening through to palliative care) for use where future trial-based or modelled economic evaluations cannot collect primary data from men and/or partners. Data Sources. A protocol was developed and registered on the international register of systematic reviews—PROSPERO. Databases searched included EBSCO Information Services (CINAHL, EconLit, Global Health, HEED, MEDLINE Complete, PsycINFO), Cochrane Database of Systematic Reviews, Web of Science, and Embase. Study Selection. Study selection terms included health-related quality of life, prostate cancer, and partners or carers. Data Extraction. The authors identified articles published between 2007 and 2016 that provided health state utility values, with statistical uncertainty, for men with or at risk of prostate cancer and/or their partner/carers. Data Synthesis and Results. Study quality and generalizability of utilities was evaluated and meta-analysis conducted against prespecified criteria. From 906 original articles, 29 recent primary studies met the inclusion/exclusion criteria. We tabulate all the utility values with uncertainty, along with considerable methodological detail and patient population characteristics. Limitations. Utility values pertaining to carers/partners were limited to one study. Conclusions. Studies varied in design, measurement instruments utilized, quality, and generalizability. There is sufficient qualitative and quantitative detail for the reported utility values to be readily incorporated into economic evaluations. More research is needed with carers/partners and with newly developing prostate cancer-specific quality of life tools.

Literature review of the burden of prostate cancer in Germany, France, the United Kingdom and Canada

BACKGROUND

Prostate cancer is the most frequently reported cancer in males in Europe, and is associated with substantial morbidity and mortality. The aim of the current review was to characterize the clinical, economic and humanistic burden of disease associated with prostate cancer in France, Germany, the UK and Canada.

METHODS

Literature searches were conducted using the PubMed, EMBASE and Cochrane Library databases to identify studies reporting incidence and/or mortality rates, costs and health state utilities associated with prostate cancer in the settings of interest. For inclusion, studies were required to be published in English in full-text form from 2006 onwards.

RESULTS

Incidence studies showed that in all settings the incidence of prostate cancer has increased substantially over the past two decades, driven in part by increased uptake of prostate specific antigen (PSA) screening leading to earlier identification of tumors, but which has also led to over-treatment, compounding the economic burden of disease. Mortality rates have declined over the same time frame, driven by earlier detection and improvements in treatment. Both prostate cancer itself, as well as treatment and treatment-related complications, are associated with reduced quality of life.

CONCLUSIONS

Prostate cancer is associated with a significant clinical and economic burden, whilst earlier detection and aggressive treatment is associated with improved survival, over-treatment of men with indolent tumors compounds the already significant burden of disease and treatment can lead to long-term side effects including impotence and impaired urinary and/or bowel function. There is currently an unmet clinical need for diagnostic and/or prognostic tools that facilitate personalized prostate cancer treatment, and potentially reduce the clinical, economic and humanistic burden of invasive cancer treatment.

Meta-analysis of predictive models to assess the clinical validity and utility for patient-centered medical decision making: application to the CAncer of the Prostate Risk Assessment (CAPRA)

BACKGROUND

The Cancer of the Prostate Risk Assessment (CAPRA) score was designed and validated several times to predict the biochemical recurrence-free survival after a radical prostatectomy. Our objectives were, first, to study the clinical validity of the CAPRA score, and, second, to assess its clinical utility for stratified medicine from an original patient-centered approach.

METHODS

We proposed a meta-analysis based on a literature search using MEDLINE. Observed and predicted biochemical-recurrence-free survivals were compared to assess the calibration of the CAPRA score. Discriminative capacities were evaluated by estimating the summary time-dependent ROC curve. The clinical utility of the CAPRA score was evaluated according to the following stratified decisions: active monitoring for low-risk patients, prostatectomy for intermediate-risk patients, or radio-hormonal therapy for high risk patients. For this purpose, we assessed CAPRA's clinical utility in terms of its ability to maximize time-dependent utility functions (i.e. Quality-Adjusted Life-Years - QALYs).

RESULTS

We identified 683 manuscripts and finally retained 9 studies. We reported good discriminative capacities with an area under the SROCt curve at 0.73 [95%CI from 0.67 to 0.79], while graphical calibration seemed acceptable. Nevertheless, we also described that the CAPRA score was unable to discriminate between the three medical alternatives, i.e. it did not allow an increase in the number of life years in perfect health (QALYs) of patients with prostate cancer.

CONCLUSIONS

We confirmed the prognostic capacities of the CAPRA score. In contrast, we were not able to demonstrate its clinical usefulness for stratified medicine from a patient-centered perspective. Our results also highlighted the confusion between clinical validity and utility. This distinction should be better considered in order to develop predictive tools useful in practice.

Evaluating the Cost-Effectiveness of Hydrogel Rectal Spacer in Prostate Cancer Radiation Therapy

PURPOSE

A hydrogel rectal spacer (HRS) is a medical device that is approved by the U.S. Food and Drug Administration to increase the separation between the prostate and rectum. We conducted a cost-effectiveness analysis of HRS use for reduction in radiation therapy (RT) toxicities in patients with prostate cancer (PC) undergoing external beam RT (EBRT).

METHODS AND MATERIALS

A multistate Markov model was constructed from the U.S. payer perspective to examine the cost-effectiveness of HRS in men with localized PC receiving EBRT (EBRT alone vs EBRT + HRS). The subgroups analyzed included site of HRS placement (hospital outpatient, physician office, ambulatory surgery center) and proportion of patients with good baseline erectile function (EF). Data on EF, gastrointestinal and genitourinary toxicities incidence, and potential risks associated with HRS implantation were obtained from a recently published randomized clinical trial. Health utilities and costs were derived from the literature and the 2018 Physician Fee Schedule and were discounted 3% annually. Quality-adjusted life years (QALYs) and costs were modeled for a 5-year period from receipt of RT. Probabilistic sensitivity analysis and value-based threshold analyses were conducted.

RESULTS

The per-patient 5-year incremental cost for spacers administered in a hospital outpatient setting was $3578, and the incremental effectiveness was 0.0371 QALYs. The incremental cost-effectiveness ratio was $96,440/QALY for patients with PC undergoing HRS insertion in a hospital and $39,286/QALY for patients undergoing HRS insertion in an ambulatory facility. For men with good baseline EF, the incremental cost-effectiveness ratio was $35,548/QALY and $9627/QALY in hospital outpatient and ambulatory facility settings, respectively.

CONCLUSIONS

Based on the current Medicare Physician Fee Schedule, HRS is cost-effective at a willingness to pay threshold of $100,000. These results contain substantial uncertainty, suggesting more evidence is needed to refine future decision-making.

Stereotactic Body Radiotherapy versus Low Dose Rate Brachytherapy for Localised Prostate Cancer: a Cost-Utility Analysis

AIMS

To conduct a cost-utility analysis comparing stereotactic body radiotherapy (SBRT) with low dose rate brachytherapy (LDR-BT) for localised prostate cancer (PCa).

MATERIALS AND METHODS

A decision-analytic Markov model was developed from the healthcare payer perspective to simulate the history of a 66-year-old man with low-risk PCa. The model followed patients yearly over their remaining lifetimes. Health states included 'recurrence-free', 'biochemical recurrence' (BR), 'metastatic' and 'death'. Transition probabilities were based on a retrospective cohort analysis undertaken at our institution. Utilities were derived from the literature. Costs were assigned in 2015 Canadian dollars ($) and reflected Ontario's health system and departmental costs. Outcomes included quality-adjusted life years (QALYs), costs and incremental cost-effectiveness ratios. A willingness-to-pay threshold of $50 000/QALY was used.

RESULTS

SBRT was the dominant strategy with 0.008LYs and 0.029QALYs gained and a reduction in cost of $2615. Under base case conditions, our results were sensitive to the BR probability associated with both strategies. LDR-BT becomes the preferred strategy if the BR with SBRT is 1.3*[baseline BR_SBRT] or if the BR with LDR-BT is 0.76*[baseline BR_LDR-BT]. When assuming the same BR for both strategies, LDR-BT becomes marginally more effective with 0.009QALYs gained at a cost of $272 848/QALY.

CONCLUSIONS

SBRT represents an economically attractive radiation strategy. Further research should be carried out to provide longer-term follow-up and high-quality evidence.

Benefits and harms of prostate cancer screening - predictions of the ONCOTYROL prostate cancer outcome and policy model

Background

A recent recalibration of the ONCOTYROL Prostate Cancer Outcome and Policy (PCOP) Model, assuming that latent prostate cancer (PCa) detectable at autopsy might be detectable by screening as well, resulted in considerable worsening of the benefit-harm balance of screening. In this study, we used the recalibrated model to assess the effects of familial risk, quality of life (QoL) preferences, age, and active surveillance.

Methods

Men with average and elevated familial PCa risk were simulated in separate models, differing in familial risk parameters. Familial risk was assumed to affect PCa onset and progression simultaneously in the base-case, and separately in scenario analyses. Evaluated screening strategies included one-time screening at different ages, and screening at different intervals and age ranges. Optimal screening strategies were identified depending on age and individual QoL preferences. Strategies were additionally evaluated with active surveillance by biennial re-biopsy delaying treatment of localized cancer until grade progression to Gleason score ≥ 7.

Results

Screening men with average PCa risk reduced quality-adjusted life expectancy (QALE) even under favorable assumptions. Men with elevated familial risk, depending on age and disutilities, gained QALE. While for men with familial risk aged 55 and 60 years annual screening to age 69 was the optimal strategy over most disutility ranges, no screening was the preferred option for 65 year-old men with average and above disutilities.

Active surveillance greatly reduced overtreatment, but QALE gains by averted adverse events were opposed by losses due to delayed treatment and additional biopsies. The effect of active surveillance on the benefit-harm balance of screening differed between populations, as net losses and gains in QALE predicted for screening without active surveillance in men with average and familial PCa risk, respectively, were both reduced.

Conclusions

Assumptions about PCa risk and screen-detectable prevalence significantly affect the benefit-harm balance of screening. Based on the assumptions of our model, PCa screening should focus on candidates with familial predisposition with consideration of individual QoL preferences and age. Active surveillance may require treatment initiation before Gleason score progression to 7. Alternative active surveillance strategies should be evaluated in further modeling studies.

Health-Related Quality of Life, Psychological Distress, and Sexual Changes Following Prostate Cancer: A Comparison of Gay and Bisexual Men with Heterosexual Men

INTRODUCTION

Decrements in health-related quality of life (HRQOL) and sexual difficulties are a recognized consequence of prostate cancer (PCa) treatment. However little is known about the experience of gay and bisexual (GB) men.

AIM

HRQOL and psychosexual predictors of HRQOL were examined in GB and heterosexual men with PCa to inform targeted health information and support.

METHOD

One hundred twenty-four GB and 225 heterosexual men with PCa completed a range of validated psychosexual instruments.

MAIN OUTCOME MEASURE

Functional Assessment of Cancer Therapy-Prostate (FACT-P) was used to measure HRQOL, with validated psychosexual measures, and demographic and treatment variables used as predictors.

RESULTS

GB men were significantly younger (64.25 years) than heterosexual men (71.54 years), less likely to be in an ongoing relationship, and more likely to have casual sexual partners. Compared with age-matched population norms, participants in both groups reported significantly lower sexual functioning and HRQOL, increased psychological distress, disruptions to dyadic sexual communication, and lower masculine self-esteem, sexual confidence, and sexual intimacy. In comparison with heterosexual men, GB men reported significantly lower HRQOL (P = .046), masculine self-esteem (P < .001), and satisfaction with treatment (P = .013); higher psychological distress (P = .005), cancer related distress (P < .001) and ejaculatory concern (P < .001); and higher sexual functioning (P < .001) and sexual confidence (P = .001). In regression analysis, psychological distress, cancer-related distress, masculine self-esteem, and satisfaction with treatment were predictors of HRQOL for GB men (R2Adj = .804); psychological distress and sexual confidence were predictors for heterosexual men (R2Adj = .690).

CONCLUSION

These findings confirm differences between GB and heterosexual men in the impact of PCa on HRQOL across a range of domains, suggesting there is a need for GB targeted PCa information and support, to address the concerns of this "hidden population" in PCa care.

The ONCOTYROL Prostate Cancer Outcome and Policy Model: Effect of Prevalence Assumptions on the Benefit-Harm Balance of Screening

BACKGROUND

The ONCOTYROL Prostate Cancer Outcome and Policy (PCOP) model is a state-transition microsimulation model evaluating the benefits and harms of prostate cancer (PCa) screening. The natural history and detection component of the original model was based on the 2003 version of the Erasmus MIcrosimulation SCreening ANalysis (MISCAN) model, which was not calibrated to prevalence data. Compared with data from autopsy studies, prevalence of latent PCa assumed by the original model is low, which may bias the model toward screening. Our objective was to recalibrate the original model to match prevalence data from autopsy studies as well and compare benefit-harm predictions of the 2 model versions differing in prevalence.

METHODS

For recalibration, we reprogrammed the natural history and detection component of the PCOP model as a deterministic Markov state-transition cohort model in the statistical software package R. All parameters were implemented as variables or time-dependent functions and calibrated simultaneously in a single run. Observed data used as calibration targets included data from autopsy studies, cancer registries, and the European Randomized Study of Screening for Prostate Cancer. Compared models were identical except for calibrated parameters.

RESULTS

We calibrated 46 parameters. Prevalence from autopsy studies could not be fitted using the original parameter set. Additional parameters, allowing for interruption of disease progression and age-dependent screening sensitivities, were needed. Recalibration to higher prevalence demonstrated a considerable increase of overdiagnosis and decline of screening sensitivity, which significantly worsened the benefit-harm balance of screening.

CONCLUSIONS

Our calibration suggests that not all cancers are at risk of progression, and screening sensitivity may be lower at older ages. PCa screening models that use calibration to simulate disease progression in the unobservable latent phase are highly sensitive to prevalence assumptions.

Estimating preferences for treatments in patients with localized prostate cancer

PURPOSE

Studies of patients' preferences for localized prostate cancer treatments have assessed radical prostatectomy and external radiation therapy, but none of them has evaluated brachytherapy. The aim of our study was to assess the preferences and willingness to pay of patients with localized prostate cancer who had been treated with radical prostatectomy, external radiation therapy, or brachytherapy, and their related urinary, sexual, and bowel side effects.

METHODS AND MATERIALS

This was an observational, prospective cohort study with follow-up until 5 years after treatment. A total of 704 patients with low or intermediate risk localized prostate cancer were consecutively recruited from 2003 to 2005. The estimation of preferences was conducted using time trade-off, standard gamble, and willingness-to-pay methods. Side effects were measured with the Expanded Prostate Index Composite (EPIC), a prostate cancer-specific questionnaire. Tobit models were constructed to assess the impact of treatment and side effects on patients' preferences. Propensity score was applied to adjust for treatment selection bias.

RESULTS

Of the 580 patients reporting preferences, 165 were treated with radical prostatectomy, 152 with external radiation therapy, and 263 with brachytherapy. Both time trade-off and standard gamble results indicated that the preferences of patients treated with brachytherapy were 0.06 utilities higher than those treated with radical prostatectomy (P=.01). Similarly, willingness-to-pay responses showed a difference of €57/month (P=.004) between these 2 treatments. Severe urinary incontinence presented an independent impact on the preferences elicited (P<.05), whereas no significant differences were found by bowel and sexual side effects.

CONCLUSIONS

Our findings indicate that urinary incontinence is the side effect with the highest impact on preferences and that brachytherapy and external radiation therapy are more valued than radical prostatectomy. These time trade-off and standard gamble preference assessments as well as the willingness-to-pay estimation could be useful to perform respectively cost-utility or cost-benefit analyses, which can guide health policy decisions.

The cost-utility of open prostatectomy compared with active surveillance in early localised prostate cancer

BACKGROUND

There is an on-going debate about whether to perform surgery on early stage localised prostate cancer and risk the common long term side effects such as urinary incontinence and erectile dysfunction. Alternatively these patients could be closely monitored and treated only in case of disease progression (active surveillance). The aim of this paper is to develop a decision-analytic model comparing the cost-utility of active surveillance (AS) and radical prostatectomy (PE) for a cohort of 65 year old men with newly diagnosed low risk prostate cancer.

METHODS

A Markov model comparing PE and AS over a lifetime horizon was programmed in TreeAge from a German societal perspective. Comparative disease specific mortality was obtained from the Scandinavian Prostate Cancer Group trial. Direct costs were identified via national treatment guidelines and expert interviews covering in-patient, out-patient, medication, aids and remedies as well as out of pocket payments. Utility values were used as factor weights for age specific quality of life values of the German population. Uncertainty was assessed deterministically and probabilistically.

RESULTS

With quality adjustment, AS was the dominant strategy compared with initial treatment. In the base case, it was associated with an additional 0.04 quality adjusted life years (7.60 QALYs vs. 7.56 QALYs) and a cost reduction of €6,883 per patient (2011 prices). Considering only life-years gained, PE was more effective with an incremental cost-effectiveness ratio of €96,420/life year gained. Sensitivity analysis showed that the probability of developing metastases under AS and utility weights under AS are a major sources of uncertainty. A Monte Carlo simulation revealed that AS was more likely to be cost-effective even under very high willingness to pay thresholds.

CONCLUSION

AS is likely to be a cost-saving treatment strategy for some patients with early stage localised prostate cancer. However, cost-effectiveness is dependent on patients' valuation of health states. Better predictability of tumour progression and modified reimbursement practice would support widespread use of AS in the context of the German health care system. More research is necessary in order to reliably quantify the health benefits compared with initial treatment and account for patient preferences.

Predicting utility scores for prostate cancer: mapping the Prostate Cancer Index to the Patient-Oriented Prostate Utility Scale (PORPUS)

BACKGROUND

The Prostate Cancer Index (PCI) is a health profile instrument that measures health-related quality of life with six subscales: urinary, sexual, and bowel function and bother. The Patient-Oriented Prostate Utility Scale (PORPUS-U) measures utility (0=dead and 1=full health). Utility is a preference-based approach to measure health-related quality of life, required for decision analyses and cost-effectiveness analyses. We developed a function to estimate PORPUS-U utilities from PCI scores.

METHODS

The development data set included 676 community-dwelling prostate cancer (PC) survivors who completed the PCI and PORPUS-U by mail. We fit three linear regression models: one used original PORPUS-U scores and two used log-transformed PORPUS-U scores, one with a hierarchy constraint and one without. The model selection was performed using stepwise selection and fivefold cross validation. The validation data included 248 PC outpatients with three assessments on the PCI and PORPUS-U. Scores were retransformed for validation, with Duan's smearing estimator applied to correct potential bias. The predictive ability of the models was assessed with R(2), root mean square error (RMSE) and by comparing predicted and observed utilities.

RESULTS

The best-fitting model used the log-transformed PORPUS-U with no hierarchy constraint. The R(2) was 0.72. The RMSE ranged from 0.040 to 0.061 for the three validation data sets. Differences between predicted and observed utilities ranged from 0.000 to 0.006 but predicted utilities overestimated the lowest 5% of observed PORPUS-U scores and underestimated the highest observed scores.

CONCLUSIONS

Our algorithm can calculate PORPUS-U utility scores from PCI scores, thus supplementing descriptive quality of life measures with utility scores in PC patients. Utilities derived from mapping algorithms are useful for assigning utility to groups of patients but are less accurate at predicting utility of individual patients. We are exploring statistical methods to improve the mapping of utilities from descriptive instruments.

Patient time and out-of-pocket costs for long-term prostate cancer survivors in Ontario, Canada

PURPOSE

Time and out-of-pocket (OOP) costs can represent a substantial burden for cancer patients but have not been described for long-term cancer survivors. We estimated these costs, their predictors, and their relationship to financial income, among a cohort of long-term prostate cancer (PC) survivors.

METHODS

A population-based, community-dwelling, geographically diverse sample of long-term (2-13 years) PC survivors in Ontario, Canada, was identified from the Ontario Cancer Registry and contacted through their referring physicians. We obtained data on demographics, health care resource use, and OOP costs through mailed questionnaires and conducted chart reviews to obtain clinical data. We compared mean annual time and OOP costs (2006 Canadian dollars) across clinical and sociodemographic characteristics and examined the association between costs and four groups of predictors (patient, disease, system, symptom) using two-part regression models.

RESULTS

Patients' (N = 585) mean age was 73 years; 77 % were retired, and 42 % reported total annual incomes less than $40,000. Overall, mean time costs were $838/year and mean OOP costs were $200/year. Although generally low, total costs represented approximately 10 % of income for lower income patients. No demographic variables were associated with costs. Radical prostatectomy, younger age, poor urinary function, current androgen deprivation therapy, and recent diagnosis were significantly associated with increased likelihood of incurring any costs, but only urinary function significantly affected total amount.

CONCLUSIONS

Time and OOP costs are modest for most long-term PC survivors but can represent a substantial burden for lower income patients. Even several years after diagnosis, PC-specific treatments and treatment-related dysfunction are associated with increased costs.

IMPLICATIONS FOR CANCER SURVIVORS

Time and out-of-pocket costs are generally manageable for long-term PC survivors but can be a significant burden mainly for lower income patients. The effects of PC-specific, treatment-related dysfunctions on quality of life can also represent sources of expense for patients.